Toss shrimp with lime juice, garlic, and 1 teaspoon salt in a large bowl. Let marinate at room temperature for 30 minutes.
Heat oil in a large skillet over medium until shimmering. Add onion, bell peppers, and scallions; cook, stirring often, until softened, about 4 minutes. Add tomatoes; cook, stirring often, until softened, about 5 minutes.
Reduce heat to medium-low; stir in coconut milk, tomato sauce, chile, and remaining 1 teaspoon salt. Simmer, stirring occasionally, until mixture is slightly reduced and thickened, about 10 minutes.
Increase heat to medium-high. Add marinated shrimp; cook, stirring often, until opaque and cooked through, 4 to 5 minutes. Remove from heat; discard chile. Garnish shrimp with cilantro; serve with rice and lime wedges.
